1 files changed, 139 insertions, 0 deletions
diff --git a/packages/markdown-it-container.mjs b/packages/markdown-it-container.mjs
new file mode 100644
index 0000000..2643284
--- /dev/null
+++ b/packages/markdown-it-container.mjs
@@ -0,0 +1,139 @@
+// Process block-level custom containers
+//
+export default function container_plugin (md, name, options) {
+  // Second param may be useful if you decide
+  // to increase minimal allowed marker length
+  function validateDefault (params/*, markup */) {
+    return params.trim().split(' ', 2)[0] === name
+  }
+
+  function renderDefault (tokens, idx, _options, env, slf) {
+    // add a class to the opening tag
+    if (tokens[idx].nesting === 1) {
+      tokens[idx].attrJoin('class', name)
+    }
+
+    return slf.renderToken(tokens, idx, _options, env, slf)
+  }
+
+  options = options || {}
+
+  const min_markers = 3
+  const marker_str  = options.marker || ':'
+  const marker_char = marker_str.charCodeAt(0)
+  const marker_len  = marker_str.length
+  const validate    = options.validate || validateDefault
+  const render      = options.render || renderDefault
+
+  function container (state, startLine, endLine, silent) {
+    let pos
+    let auto_closed = false
+    let start = state.bMarks[startLine] + state.tShift[startLine]
+    let max = state.eMarks[startLine]
+
+    // Check out the first character quickly,
+    // this should filter out most of non-containers
+    //
+    if (marker_char !== state.src.charCodeAt(start)) { return false }
+
+    // Check out the rest of the marker string
+    //
+    for (pos = start + 1; pos <= max; pos++) {
+      if (marker_str[(pos - start) % marker_len] !== state.src[pos]) {
+        break
+      }
+    }
+
+    const marker_count = Math.floor((pos - start) / marker_len)
+    if (marker_count < min_markers) { return false }
+    pos -= (pos - start) % marker_len
+
+    const markup = state.src.slice(start, pos)
+    const params = state.src.slice(pos, max)
+    if (!validate(params, markup)) { return false }
+
+    // Since start is found, we can report success here in validation mode
+    //
+    if (silent) { return true }
+
+    // Search for the end of the block
+    //
+    let nextLine = startLine
+
+    for (;;) {
+      nextLine++
+      if (nextLine >= endLine) {
+        // unclosed block should be autoclosed by end of document.
+        // also block seems to be autoclosed by end of parent
+        break
+      }
+
+      start = state.bMarks[nextLine] + state.tShift[nextLine]
+      max = state.eMarks[nextLine]
+
+      if (start < max && state.sCount[nextLine] < state.blkIndent) {
+        // non-empty line with negative indent should stop the list:
+        // - ```
+        //  test
+        break
+      }
+
+      if (marker_char !== state.src.charCodeAt(start)) { continue }
+
+      if (state.sCount[nextLine] - state.blkIndent >= 4) {
+        // closing fence should be indented less than 4 spaces
+        continue
+      }
+
+      for (pos = start + 1; pos <= max; pos++) {
+        if (marker_str[(pos - start) % marker_len] !== state.src[pos]) {
+          break
+        }
+      }
+
+      // closing code fence must be at least as long as the opening one
+      if (Math.floor((pos - start) / marker_len) < marker_count) { continue }
+
+      // make sure tail has spaces only
+      pos -= (pos - start) % marker_len
+      pos = state.skipSpaces(pos)
+
+      if (pos < max) { continue }
+
+      // found!
+      auto_closed = true
+      break
+    }
+
+    const old_parent = state.parentType
+    const old_line_max = state.lineMax
+    state.parentType = 'container'
+
+    // this will prevent lazy continuations from ever going past our end marker
+    state.lineMax = nextLine
+
+    const token_o  = state.push('container_' + name + '_open', 'div', 1)
+    token_o.markup = markup
+    token_o.block  = true
+    token_o.info   = params
+    token_o.map    = [startLine, nextLine]
+
+    state.md.block.tokenize(state, startLine + 1, nextLine)
+
+    const token_c  = state.push('container_' + name + '_close', 'div', -1)
+    token_c.markup = state.src.slice(start, pos)
+    token_c.block  = true
+
+    state.parentType = old_parent
+    state.lineMax = old_line_max
+    state.line = nextLine + (auto_closed ? 1 : 0)
+
+    return true
+  }
+
+  md.block.ruler.before('fence', 'container_' + name, container, {
+    alt: ['paragraph', 'reference', 'blockquote', 'list']
+  })
+  md.renderer.rules['container_' + name + '_open'] = render
+  md.renderer.rules['container_' + name + '_close'] = render
+};